package com.kada.mht.lucene.test;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Date;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

/**
 * Description Of The Class<br>
 * 
 * @author Jimmy Mu
 * @version 1.000, 2012-5-30
 * 
 */
public class SearchFiles {
    
    private SearchFiles() {
    }
    
    /** Simple command-line based search demo. */
    public static void main(String[] args) throws Exception {
        String usage = "Usage:\tjava org.apache.lucene.demo.SearchFiles [-index dir] [-field f] [-repeat n] [-queries file] [-query string] [-raw] [-paging hitsPerPage]\n\nSee http://lucene.apache.org/java/4_0/demo.html for details.";
        if (args.length > 0
                && ("-h".equals(args[0]) || "-help".equals(args[0])))
        {
            System.out.println(usage);
            System.exit(0);
        }
        
        String index = "index";
        String field = "contents";
        String queries = null;
        int repeat = 0;
        boolean raw = false;
        String queryString = null;
        int hitsPerPage = 10;
        
        for (int i = 0; i < args.length; i++) {
            if ("-index".equals(args[i])) {
                index = args[i + 1];
                i++;
            } else if ("-field".equals(args[i])) {
                field = args[i + 1];
                i++;
            } else if ("-queries".equals(args[i])) {
                queries = args[i + 1];
                i++;
            } else if ("-query".equals(args[i])) {
                queryString = args[i + 1];
                i++;
            } else if ("-repeat".equals(args[i])) {
                repeat = Integer.parseInt(args[i + 1]);
                i++;
            } else if ("-raw".equals(args[i])) {
                raw = true;
            } else if ("-paging".equals(args[i])) {
                hitsPerPage = Integer.parseInt(args[i + 1]);
                if (hitsPerPage <= 0) {
                    System.err
                            .println("There must be at least 1 hit per page.");
                    System.exit(1);
                }
                i++;
            }
        }
        
        IndexReader reader = IndexReader
                .open(FSDirectory.open(new File(index)));
        IndexSearcher searcher = new IndexSearcher(reader);
        Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_31);
        
        BufferedReader in = null;
        if (queries != null) {
            in = new BufferedReader(new InputStreamReader(new FileInputStream(
                    queries), "UTF-8"));
        } else {
            in = new BufferedReader(new InputStreamReader(System.in, "UTF-8"));
        }
        QueryParser parser = new QueryParser(Version.LUCENE_31, field, analyzer);
        while (true) {
            if (queries == null && queryString == null) { // prompt the user
                System.out.println("Enter query: ");
            }
            
            String line = queryString != null ? queryString : in.readLine();
            
            if (line == null || line.length() == -1) {
                break;
            }
            
            line = line.trim();
            if (line.length() == 0) {
                break;
            }
            
            Query query = parser.parse(line);
            System.out.println("Searching for: " + query.toString(field));
            
            if (repeat > 0) { // repeat & time as benchmark
                Date start = new Date();
                for (int i = 0; i < repeat; i++) {
                    searcher.search(query, null, 100);
                }
                Date end = new Date();
                System.out.println("Time: " + (end.getTime() - start.getTime())
                        + "ms");
            }
            
            doPagingSearch(in, searcher, query, hitsPerPage, raw,
                    queries == null && queryString == null);
            
            if (queryString != null) {
                break;
            }
        }
        searcher.close();
        reader.close();
    }
    
    /**
     * This demonstrates a typical paging search scenario, where the search
     * engine presents pages of size n to the user. The user can then go to the
     * next page if interested in the next hits.
     * 
     * When the query is executed for the first time, then only enough results
     * are collected to fill 5 result pages. If the user wants to page beyond
     * this limit, then the query is executed another time and all hits are
     * collected.
     * 
     */
    public static void doPagingSearch(BufferedReader in,
            IndexSearcher searcher, Query query, int hitsPerPage, boolean raw,
            boolean interactive) throws IOException
    {
        
        // Collect enough docs to show 5 pages
        TopDocs results = searcher.search(query, 5 * hitsPerPage);
        ScoreDoc[] hits = results.scoreDocs;
        
        int numTotalHits = results.totalHits;
        System.out.println(numTotalHits + " total matching documents");
        
        int start = 0;
        int end = Math.min(numTotalHits, hitsPerPage);
        
        while (true) {
            if (end > hits.length) {
                System.out.println("Only results 1 - " + hits.length + " of "
                                + numTotalHits + " total matching documents collected.");
                System.out.println("Collect more (y/n) ?");
                String line = in.readLine();
                if (line.length() == 0 || line.charAt(0) == 'n') {
                    break;
                }
                
                hits = searcher.search(query, numTotalHits).scoreDocs;
            }
            
            end = Math.min(hits.length, start + hitsPerPage);
            
            for (int i = start; i < end; i++) {
                if (raw) { // output raw format
                    System.out.println("doc=" + hits[i].doc + " score="
                            + hits[i].score);
                    continue;
                }
                
                Document doc = searcher.doc(hits[i].doc);
                String path = doc.get("path");
                if (path != null) {
                    System.out.println((i + 1) + ". " + path);
                    String title = doc.get("title");
                    if (title != null) {
                        System.out.println("   Title: " + doc.get("title"));
                    }
                } else {
                    System.out.println((i + 1) + ". "
                            + "No path for this document");
                }
                
            }
            
            if (!interactive || end == 0) {
                break;
            }
            
            if (numTotalHits >= end) {
                boolean quit = false;
                while (true) {
                    System.out.print("Press ");
                    if (start - hitsPerPage >= 0) {
                        System.out.print("(p)revious page, ");
                    }
                    if (start + hitsPerPage < numTotalHits) {
                        System.out.print("(n)ext page, ");
                    }
                    System.out
                            .println("(q)uit or enter number to jump to a page.");
                    
                    String line = in.readLine();
                    if (line.length() == 0 || line.charAt(0) == 'q') {
                        quit = true;
                        break;
                    }
                    if (line.charAt(0) == 'p') {
                        start = Math.max(0, start - hitsPerPage);
                        break;
                    } else if (line.charAt(0) == 'n') {
                        if (start + hitsPerPage < numTotalHits) {
                            start += hitsPerPage;
                        }
                        break;
                    } else {
                        int page = Integer.parseInt(line);
                        if ((page - 1) * hitsPerPage < numTotalHits) {
                            start = (page - 1) * hitsPerPage;
                            break;
                        } else {
                            System.out.println("No such page");
                        }
                    }
                }
                if (quit)
                    break;
                end = Math.min(numTotalHits, start + hitsPerPage);
            }
        }
    }
}
